What Is the Normal Range for IQ Scores?

What Is the Normal Range for IQ Scores?

What Is the Normal Range for IQ Scores?

Most IQ scores fall within 15 points of a median score of 100. A normal distribution of IQ scores around this median means that 86 percent of scores fall within one standard deviation, or between 85 and 115. All but 5 percent fall within two standard deviations.

IQ tests are calibrated in order to establish a median score of 100, which is usually regarded as average. The further a score deviates from the median, the fewer people achieve it. Only a small fraction of test takers score higher than 130 or lower than 70, which are usually considered the bounds of normal IQs.